diff --git a/tools/pydfu.py b/tools/pydfu.py
index 030f56bf85..8b8e338981 100755
--- a/tools/pydfu.py
+++ b/tools/pydfu.py
@@ -22,6 +22,8 @@ import sys
 import usb.core
 import usb.util
 import zlib
+import time
+import math
 
 # VID/PID
 __VID = 0x0483
@@ -29,6 +31,8 @@ __PID = 0xDF11
 
 # USB request __TIMEOUT
 __TIMEOUT = 4000
+__NEXT_TIMEOUT = 0
+__STATUS_TIMEOUT = 20000
 
 # DFU commands
 __DFU_DETACH = 0
@@ -95,6 +99,13 @@ else:
         return usb.util.get_string(dev, index)
 
 
+def timeout():
+    global __NEXT_TIMEOUT
+    t = max(__TIMEOUT, __NEXT_TIMEOUT)
+    __NEXT_TIMEOUT = 0
+    return int(math.ceil(t))
+
+
 def find_dfu_cfg_descr(descr):
     if len(descr) == 9 and descr[0] == 9 and descr[1] == _DFU_DESCRIPTOR_TYPE:
         nt = collections.namedtuple(
@@ -150,17 +161,32 @@ def init():
 
 def abort_request():
     """Sends an abort request."""
-    __dev.ctrl_transfer(0x21, __DFU_ABORT, 0, __DFU_INTERFACE, None, __TIMEOUT)
+    __dev.ctrl_transfer(0x21, __DFU_ABORT, 0, __DFU_INTERFACE, None, timeout())
 
 
 def clr_status():
     """Clears any error status (perhaps left over from a previous session)."""
-    __dev.ctrl_transfer(0x21, __DFU_CLRSTATUS, 0, __DFU_INTERFACE, None, __TIMEOUT)
+    __dev.ctrl_transfer(0x21, __DFU_CLRSTATUS, 0, __DFU_INTERFACE, None, timeout())
 
 
 def get_status():
     """Get the status of the last operation."""
-    stat = __dev.ctrl_transfer(0xA1, __DFU_GETSTATUS, 0, __DFU_INTERFACE, 6, 20000)
+    _timeout = time.time() + max(__STATUS_TIMEOUT, timeout())
+    stat = None
+    while time.time() < _timeout:
+        try:
+            stat = __dev.ctrl_transfer(
+                0xA1, __DFU_GETSTATUS, 0, __DFU_INTERFACE, 6, int(_timeout - time.time())
+            )
+            break
+        except usb.core.USBError as ex:
+            # If the firmware is blocked the transfer can timeout much quicker than
+            # the supplied timeout. If so, retry until the overall timeout is used up.
+            if "Operation timed out" not in str(ex):
+                raise
+
+    if stat is None:
+        raise SystemExit("DFU: get_status timed out")
 
     # firmware can provide an optional string for any error
     if stat[5]:
@@ -168,6 +194,12 @@ def get_status():
         if message:
             print(message)
 
+    # firmware can send a longer timeout request while it's performing slow operation eg. erase
+    timeout_ms = stat[1] << 16 | stat[2] << 8 | stat[3]
+    if timeout_ms:
+        global __NEXT_TIMEOUT
+        __NEXT_TIMEOUT = __TIMEOUT + timeout_ms
+
     return stat[4]
 
 
@@ -180,9 +212,9 @@ def check_status(stage, expected):
 def mass_erase():
     """Performs a MASS erase (i.e. erases the entire device)."""
     # Send DNLOAD with first byte=0x41
-    __dev.ctrl_transfer(0x21, __DFU_DNLOAD, 0, __DFU_INTERFACE, "\x41", __TIMEOUT)
+    __dev.ctrl_transfer(0x21, __DFU_DNLOAD, 0, __DFU_INTERFACE, "\x41", timeout())
 
-    # Execute last command
+    # Execute erase and wait until complete
     check_status("erase", __DFU_STATE_DFU_DOWNLOAD_BUSY)
 
     # Check command state
@@ -196,7 +228,7 @@ def page_erase(addr):
 
     # Send DNLOAD with first byte=0x41 and page address
     buf = struct.pack("<BI", 0x41, addr)
-    __dev.ctrl_transfer(0x21, __DFU_DNLOAD, 0, __DFU_INTERFACE, buf, __TIMEOUT)
+    __dev.ctrl_transfer(0x21, __DFU_DNLOAD, 0, __DFU_INTERFACE, buf, timeout())
 
     # Execute last command
     check_status("erase", __DFU_STATE_DFU_DOWNLOAD_BUSY)
@@ -209,7 +241,7 @@ def set_address(addr):
     """Sets the address for the next operation."""
     # Send DNLOAD with first byte=0x21 and page address
     buf = struct.pack("<BI", 0x21, addr)
-    __dev.ctrl_transfer(0x21, __DFU_DNLOAD, 0, __DFU_INTERFACE, buf, __TIMEOUT)
+    __dev.ctrl_transfer(0x21, __DFU_DNLOAD, 0, __DFU_INTERFACE, buf, timeout())
 
     # Execute last command
     check_status("set address", __DFU_STATE_DFU_DOWNLOAD_BUSY)
@@ -243,7 +275,7 @@ def write_memory(addr, buf, progress=None, progress_addr=0, progress_size=0):
         # Send DNLOAD with fw data
         chunk = min(__cfg_descr.wTransferSize, xfer_total - xfer_bytes)
         __dev.ctrl_transfer(
-            0x21, __DFU_DNLOAD, 2, __DFU_INTERFACE, buf[xfer_bytes : xfer_bytes + chunk], __TIMEOUT
+            0x21, __DFU_DNLOAD, 2, __DFU_INTERFACE, buf[xfer_bytes : xfer_bytes + chunk], timeout()
         )
 
         # Execute last command
@@ -267,7 +299,7 @@ def write_page(buf, xfer_offset):
     set_address(xfer_base + xfer_offset)
 
     # Send DNLOAD with fw data
-    __dev.ctrl_transfer(0x21, __DFU_DNLOAD, 2, __DFU_INTERFACE, buf, __TIMEOUT)
+    __dev.ctrl_transfer(0x21, __DFU_DNLOAD, 2, __DFU_INTERFACE, buf, timeout())
 
     # Execute last command
     check_status("write memory", __DFU_STATE_DFU_DOWNLOAD_BUSY)
@@ -285,7 +317,7 @@ def exit_dfu():
     set_address(0x08000000)
 
     # Send DNLOAD with 0 length to exit DFU
-    __dev.ctrl_transfer(0x21, __DFU_DNLOAD, 0, __DFU_INTERFACE, None, __TIMEOUT)
+    __dev.ctrl_transfer(0x21, __DFU_DNLOAD, 0, __DFU_INTERFACE, None, timeout())
 
     try:
         # Execute last command